THE last of three penalty saves by Mark Bosnich enabled Aston Villa to overcome Tranmere in a dramatic shoot-out after an additional half- hour had failed to separate the combatants in their Coca-Cola Cup semi- final second leg at Villa Park yesterday.

Villa, who will now contest the trophy with Manchester United or Sheffield Wednesday on 27 March, thus reached their first Wembley final in 17 years and their sixth in a competition that has had more incarnations than Dr Who.

Amid the euphoria following Bosnich's crucial save from Ian Nolan, Tranmere supporters may have been wondering whether the Australian goalkeeper should still have been on the pitch to make it.

In the 26th minute, by which time Villa had already cancelled out the First Division side's 3-1 first-leg lead, Bosnich blatantly fouled John Aldridge as the Irish international went round him. Allan Gunn pointed straight to the spot, from which Aldridge duly scored, but failed to show Bosnich a yellow card, let alone the red permitted by the laws.

While the true significance of Bosnich's reprieve was not to become apparent until much later - he is a penalty specialist, with three saves this season - Tranmere should have sensed long before then that they were not destined to reach a fifth Wembley showpiece in four years. Yet remarkably, they had been within two minutes of an aggregate victory when Dalian Atkinson sent the tie into extra time.

Even then, in the last seconds of normal time, Liam O'Brien hit a 30- yard free-kick against the inside of Bosnich's left-hand post. Villa, who put Eric Nixon's goal under siege for virtually the entire afternoon, breathed again.

The hosts had burst out of the traps as if intending to level the scores before Tranmere had adjusted to the atmosphere. Their enthusiasm to push forward almost cost them dearly in the sixth minute, when only a late Shaun Teale tackle denied Aldridge a certain goal.

The ball broke to Pat Nevin, who was thwarted by a stunning double save by Bosnich. Immediately, Chris Malkin miscued when it appeared simpler to score, and Villa celebrated their triple escape with two goals in the space of five minutes.

Dean Saunders put them ahead in the 19th minute with an instinctive finish at the near post from Andy Townsend's low cross. Teale, who epitomised Villa's bulldog spirit, then dived to head the second after a quickly taken free-kick had caught Tranmere napping and gave Ray Houghton time to pick him out with a cross.

However, Tranmere promptly reduced the deficit and restored their overall advantage through Aldridge's penalty, and despite frantic pressure by the Premiership team were edging nervously towards their first major final when they were again caught out at a set-piece in the 88th minute. Tony Daley was unmarked as he received Houghton's free-kick, and his centre was headed past Nixon by the unmarked Atkinson six yards out.

The Villa manager, Ron Atkinson, danced in delight, but was somewhat less animated as O'Brien all but negated the need for extra time. Earl Barrett struck the same upright in the 106th minute.

So to the purgatory of penalties. With Villa 3-2 up after five kicks, Bosnich saved from Ged Brannan. But Ugo Ehiogu, forced into action by the apparent reluctance of more senior players to accept responsibility, struck the bar with the shot that would have clinched it at 5-4.

When Kevin Richardson fired over with the first of the sudden- death kicks, O'Brien stepped up with a chance to win it for Tranmere, only for Bosnich to parry plunging to his right. Daley scored emphatically before the hapless Nolan saw his penalty brilliantly blocked.

The pitch was flooded with thousands of fans, who carried Bosnich off at shoulder-height. Ron Atkinson was left to savour a third League Cup final with different clubs - Wednesday and United peculiarly being the others - but for Tranmere there were only tears for souvenirs.